1. Field of the Invention
The present invention relates to a slide switch comprising a control member slidable along an imaginary plane and pressable in a direction perpendicular to the imaginary plane, a plurality of transverse contacts arranged to surround the control member, and a vertical contact having a plurality of electrode portions associated with the plurality of transverse contacts to be conductive with any one of the transverse contacts when the control member is slid.
2. Description of the Related Art
Japanese Patent Application “Kokai” No. 2003-31076 (paragraphs [0022] to [0038], and FIGS. 2 to 6) discloses a slide switch including an biasing member formed of elastomer, having four projections, and mounted in a casing, a sliding member fitted into a central portion of the biasing member, and a keytop connected to the sliding member. In this slide switch, four conductive elements are provided on outer peripheries of the biasing member while electrodes are arranged on inner walls of the casing in positions opposed to the conductive elements. With this arrangement, the keytop in a non-operative state is maintained in a neutral position by a biasing force exerted from the biasing member, and the conductive elements contact the electrodes to establish a conductive state when the keytop is operated. Also, this switch has a slider fitted into a side of the sliding member facing away from the keytop. The conductive elements are arranged in positions to contact the slider, and the electrodes are arranged in positions corresponding to the conductive elements. Each conductive element has a construction having a central portion projecting toward the slider. When the keytop is depressed, the conductive element is elastically deformed to contact the electrode thereby establishing a conductive state.
Japanese Patent Application “Kokai” No. 2003-50667 (paragraphs [0012] to [0026], and FIGS. 1 to 7) discloses a slide switch comprising a spacer, a control button, a return spring, a plunger, a sensing spring and a reverse spring laid one over another in a space between a base and a cover. In this slide switch, a knob of the control button projects to a center hole formed in the cover, and a biasing force is exerted on the control button from the return spring. A conductive rubber element is attached to a bottom surface of the control button, and guide projections are formed in a central portion of the bottom surface of the control button to be engageable with guide recesses formed in a top surface of the plunger. The guide recesses of the plunger are formed as grooves radially extending in eight directions from the center of the plunger. The plunger has a pressing projection formed in a bottom surface thereof, and an engaging projection formed in outer peripheries thereof to be engageable with the base for limiting rotation. The base has a central fixed contact provided in a circular recess formed in a central portion thereof, and peripheral fixed contacts formed in outer peripheries of the circular recess. The reverse spring and the sensing spring are arranged as corresponding to the circular recess.
With the construction of this conventional slide switch, the guide projections formed in the bottom surface of the control button are guided by the guide recesses of the plunger when the control button is slid, thereby allowing the button to be operated in eight directions. This sliding operation allows the conductive rubber element attached to the bottom surface of the control button to contact the peripheral vertical contacts of the base, thereby to electrically detect an operating direction. Further, when the control button is pressed while being slid, this operating force is transmitted to the reverse spring through the plunger. The central portion of the reverse spring contacts the central vertical contact thereby to electrically detect the pressing operation.
Recently, as switches provided in relatively small devices such as mobile phones, PDA's, game equipment controllers and remote controllers, and the like, high-performance switches capable of being slid and pressed such as the slide switches disclosed in the above-noted publications have been desired, along with their downsizing. Further, from the aspect of the sense of operation, the sense of click and a smooth sliding operation are often desired. Also, in executing the sliding operation and the pressing operation at the same time, the sense of operation is enhanced by stabilizing the posture of the control member when pressed.
According to the slide switches disclosed in the above-noted publications where the control member in a non-operative state is positioned in the central position in plan view, the contacts for detecting a pressing operation of the control member and the springs for biasing the control member upward are located in the central position. Thus, the pressing force acts upon a position offset from the central position when the control member is pressed while being slid. The control member is inclined by the force unevenly applied to the control member to vary the stroke of the pressing operation and weaken the sense of operation. Further, the inclination of the control member causes malfunction.
Moreover, in the case of a switch using a member having a dome-shaped construction as a spring for biasing the control member upward, when the control member is pressed while being slid, the pressing force acts on a position offset from the central position of the dome, as a result of which the life of the dome-shaped spring is shortened.